(Joking apart, the UK is in the middle of it's largest ever amount of UFO sightings, very strange!... if you believe it )

UFOs are being reported from... well, like ancient times. One could assume that since in modern times, high quality digital cameras are cheap and common, the number of good pictures would increase substantially. I think it does not. (Unless I missed "Razor sharp pictures of UFOs taken!" kind of news lately...)

Of course, non-existence of proof is not proof of non-existence. I suppose the best approach is to be sceptically hopeful: be sceptical until extraterrestrial origin is proved and hope that one day such proof will appear. As Carl Sagan once said: extraordinary claims require extraordinary proofs.